McCoy rubs his fingers together, palms slick with sweat. The Vulcan winds no longer feel cold to him, but they are not the reason his mouth is dry and his hands twitch with nervous energy.

Today is the day.

Today they leave Vulcan… forever, probably. Today he voluntarily hands over his freedom, his future… say goodbye to grassy open plains and homegrown food, Leonard. Today is the day.

Despite his maudlin musings, there is a nervous excited energy burning at his fingers and in his chest, and he cannot keep his eyes off Spock. Spock, who has found it necessary to, as earnestly and innocently as McCoy has ever seen him, apologize for 'misplacing his uniform' and immediately reinstate himself on active duty.

Well, if Spock has taken leave of his senses, and Jim is too star-struck with his return to see past the rightness of Spock at his science station, then the burden of sanity fell to McCoy. It was, he had to admit, a relief to be in any condition to bear that burden again.

"Are you sure this is such a bright idea?"

"What do you mean," Jim deflects, as if he doesn't know exactly what Bones is harping on.

"I mean him, back at his post, like nothing happened. I don't know if you've got the whole picture or not, but he isn't exactly working on all thrusters."

"It'll come back to him," Jim hedges, glancing away at Spock with more longing and optimism in his gaze than steady confidence.

"Are you sure?" Bones presses relentlessly, only for Jim to break his gaze and turn away, forcing McCoy to swallow his own stubborn hope. "That's what I thought."

McCoy falls back, then, moving to the back of the bridge. He can hardly blame Jim for wanting Spock at his station one last time - the last time any of them will be together. As long as he can remind Jim that Spock isn't as put-together as his composure might have them believe… that'll be enough. There's a part of him that worries for Spock too - worries that they're demanding too much too quickly, that Spock's fragile recovery could be damaged somehow… but it's not as if they're likely to put many demands on a science officer while ferrying themselves home.

Sulu engages the thrusters on command, and McCoy braces himself as his stomach flips over with the lurch. He'll never get used to these blasted contraptions, and Klingon vessels are even worse than the Federations', especially taking off from a high grav planet like Vulcan. Not that he'll ever have to repeat the experience, he supposes… unless they let him out in 30-40 years for good behavior.

He putters about the bridge for a while, nervous energy spurring his feet as he glances back and forth from Jim to the viewscreen to Spock to Jim and back again. Jim is laser focused on the view ahead of him - God only knows what's running through his mind right now, and Leonard can't even consider disturbing him. It's irrational for him to be so apprehensive about approaching Spock (doesn't he have enough rational things to worry about right now?) but his nerves are tangled just the same. He starts conversations with Spock over and over in his head, trying to find the right way to break the ice, to somehow say the right thing… but each option isn't good enough, and he only goes in circles.

When Jim remarks on the lack of Federation patrol vessels and consults Uhura on making something out of the garbled transmissions choking the comms, McCoy breaks. He only has this one chance, and who knows if they'll even let Spock talk to the crazy human felons once they reach Earth.

Bones practically throws himself forward, dropping into the seat beside Spock, fingers tingling in anticipation. For all his recitals the first word to come out of his mouth is -

"Hi. You busy?" He's grinning like a fool, he knows (Spock is alive and back at his station and Bones was worried before but watching Spock manipulate the controls like a natural has been like a balm for his nerves because he looks so right and he used to be a corpse in the morgue but he's alright now and they can have this moment he never thought they'd have any moments again)... but he can hardly stop himself given the circumstances.

Spock clearly takes a second to process his question, expression intent but unguarded. "Uhura is busy. I am monitoring." It isn't a bad reaction, but it isn't much to go on, either.

"Hm," he murmurs, already planning out what he's going to say. Spock's been indoctrinated by the hobgoblins again, after all, and Bones has to know how much he remembers. "I just wanted to say it sure is nice to have your katra back in your head and not mine."

Spock nods, before returning his attention to his instruments, but McCoy barely loses a beat before plowing on. "What I mean is, I might have carried your soul, but I still couldn't fill your shoes." Spock remembered how to speak English, after all. If he remembered words and grammar then maybe…

Spock just stares at him blankly for a second, not even raising that infuriating eyebrow. "...My shoes."

And Bones feels the smile slide off his face. Spock had never had as much trouble with metaphors as he claimed. With his eidetic memory, even if he didn't understand the spirit of metaphors, he could still remember their meaning, and his pointed ribbing at human phrasing was a well-worn joke between them.

It wasn't a joke now. It shouldn't hurt the way it does, knowing that a piece of Spock, a subconscious piece of his memory, of the banter they used to have with each other was gone… but there was nothing to do but push past it.

"...Forget it."

Spock certainly seems to, leaning back in his chair and sighing as he refocuses on the panel in front of him. His posture is stiffer than before, but McCoy has never given up easily. So Spock doesn't remember metaphors. Fine. There was more to their relationship than feigned misunderstandings. Subconsciously pressing a thumb against his lip, a thousand briefings, arguments, conversations flash through his mind, debates over logic and emotion, life and death, purpose and duty. He straightens as the idea hits him, glancing up at Spock, who's gaze is still firmly fixed on his work.

"Perhaps we could cover a little philosophical ground." He offers eagerly. "Life… death… life… things of that nature." He doesn't know exactly what he's proposing - he and Spock didn't sit down to discuss philosophy… their discussions just happened, and usually over a disagreement. But this was something they could do together. Something that meant something to them.

Spock straightens, head partially turned towards him and… is that an eye roll? Spock almost seems… annoyed, now, running out of patience for the brief conversation, and when he speaks it is with an edge in his voice.

"I did not have time on Vulcan to review the philosophical disciplines."

This wasn't right. Spock wasn't thinking, he couldn't be. They knew each other, They were important to each other. Spock was important to him. Their psychic connection through Spock's katra in the medbay rang in the forefront of his mind, and if McCoy could only find the right words to make him see

"Come on Spock, it's me, McCoy! You really have gone where no man's gone before. Can't you tell me what it felt like?" The old Spock would never turn something like this down. Would never be able to keep from sharing an experience like that, would never keep his opinion from Leonard of all people.

But Spock is sitting before him now, unmoved, dismissive. "It would be impossible to discuss the subject without a common frame of reference." And it isn't so much that Spock doesn't have the words to discuss his experience… it's that he doesn't care. Doesn't care to discuss it, doesn't care to engage with McCoy…

"You're joking."

"A joke is… a story with a humorous climax?"

He's proud. Spock is proud that he remembered the definition of a joke. Something so basic to interacting with humans, something he'd understood implicitly only a few weeks ago… Spock's biting humor, his sharp-edged wit… gone, as if it had never existed.

It's enough to shake Leonard's foundation, enough to scare him, and he's only ever interacted with Spock in one way when he's scared.

"You mean I have to die to discuss your insights on death?!" Aggression. Baiting. Because as long as Bones has known him, even before they were brothers, before they were friends, when they were barely even acquaintances… Bones has always been able to bait Spock into an argument. It is the one universal constant of their relationship.

"Forgive me, doctor. I am recieving a number of distress calls." Spock won't even look at Leonard now, gaze fixed on the wall as he monitors Uhura's transmissions.

Ice. Ice up and down Leonard's spine. Ice clenching his heart, ice settling in his gut. Ice numbing his fingers, stealing the air from his lungs, sending him reeling…

"I don't doubt it," he manages, stumbling away with far less grace than with he came.

He never thought he'd see the day Spock didn't care enough to argue with him.